This proposal is submitted in response to the RFA DK-06-504 for continuing our role as a Genetic Research Center (GRC) of the NIDDK Inflammatory Bowel Disease Genetics Consortium (IBDGC). Cedars-Sinai Medical Center will collaborate with the University of Puerto Rico for this project; UPR will be responsible for recruiting IBD patients, and CSMC will be responsible for performing genetic tests (genotyping) and analyzing the results, looking for regions of the human genome that contain genes that increase the risk for IBD. The Puerto Rican population is particularly suited for this type of study; the population is a composite of Native-American, African, and Caucasian-European peoples that have mixed together genetically since the time of Columbus. This type of genetic analysis is termed "Mapping by Admixture Linkage Disequilibrium." [unreadable] [unreadable]